Conclusion Overall, we did not observe a significant association between serum 25-OHD concentrations and the risk of ovarian cancer. However, we found evidence suggestive of an increased risk among women with low to insufficient serum 25-OHD concentrations.

Overall, our results do not suggest that plasma vitamin D levels are associated with risk of ovarian cancer. However, we observed significant associations in some subgroups, which should be evaluated further in other studies because increasing vitamin D intake is an easy preventive measure to adopt.